/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: FilterExprIterator.java,v 1.2.4.2 2005/09/14 19:45:22 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.axes;

import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xpath.internal.Expression;
import com.sun.org.apache.xpath.internal.ExpressionOwner;
import com.sun.org.apache.xpath.internal.XPathVisitor;
import com.sun.org.apache.xpath.internal.objects.XNodeSet;

public class FilterExprIterator extends BasicTestIterator {
    static final long serialVersionUID = 2552176105165737614L;
    /** The contained expression. Should be non-null.
     *  @serial   */
    private Expression m_expr;

    /** The result of executing m_expr.  Needs to be deep cloned on clone op.  */
    transient private XNodeSet m_exprObj;

    private boolean m_mustHardReset = false;
    private boolean m_canDetachNodeset = true;

    /**
     * Create a FilterExprIterator object.
     *
     */
    public FilterExprIterator() {
        super(null);
    }

    /**
     * Create a FilterExprIterator object.
     *
     */
    public FilterExprIterator(Expression expr) {
        super(null);
        m_expr = expr;
    }

    /**
     * Initialize the context values for this expression
     * after it is cloned.
     *
     * @param context The XPath runtime context for this
     * transformation.
     */
    public void setRoot(int context, Object environment) {
        super.setRoot(context, environment);

        m_exprObj = FilterExprIteratorSimple.executeFilterExpr(context, m_execContext, getPrefixResolver(), getIsTopLevel(), m_stackFrame, m_expr);
    }

    /**
     * Get the next node via getNextXXX.  Bottlenecked for derived class override.
     * @return The next node on the axis, or DTM.NULL.
     */
    protected int getNextNode() {
        if (null != m_exprObj) {
            m_lastFetched = m_exprObj.nextNode();
        } else
            m_lastFetched = DTM.NULL;

        return m_lastFetched;
    }

    /**
     * Detaches the walker from the set which it iterated over, releasing
     * any computational resources and placing the iterator in the INVALID
     * state.
     */
    public void detach() {
        super.detach();
        m_exprObj.detach();
        m_exprObj = null;
    }

    /**
     * This function is used to fixup variables from QNames to stack frame
     * indexes at stylesheet build time.
     * @param vars List of QNames that correspond to variables.  This list
     * should be searched backwards for the first qualified name that
     * corresponds to the variable reference qname.  The position of the
     * QName in the vector from the start of the vector will be its position
     * in the stack frame (but variables above the globalsTop value will need
     * to be offset to the current stack frame).
     */
    public void fixupVariables(java.util.Vector vars, int globalsSize) {
        super.fixupVariables(vars, globalsSize);
        m_expr.fixupVariables(vars, globalsSize);
    }

    /**
     * Get the inner contained expression of this filter.
     */
    public Expression getInnerExpression() {
        return m_expr;
    }

    /**
     * Set the inner contained expression of this filter.
     */
    public void setInnerExpression(Expression expr) {
        expr.exprSetParent(this);
        m_expr = expr;
    }

    /**
     * Get the analysis bits for this walker, as defined in the WalkerFactory.
     * @return One of WalkerFactory#BIT_DESCENDANT, etc.
     */
    public int getAnalysisBits() {
        if (null != m_expr && m_expr instanceof PathComponent) {
            return ((PathComponent) m_expr).getAnalysisBits();
        }
        return WalkerFactory.BIT_FILTER;
    }

    /**
     * Returns true if all the nodes in the iteration well be returned in document
     * order.
     * Warning: This can only be called after setRoot has been called!
     *
     * @return true as a default.
     */
    public boolean isDocOrdered() {
        return m_exprObj.isDocOrdered();
    }

    class filterExprOwner implements ExpressionOwner {
        /**
        * @see ExpressionOwner#getExpression()
        */
        public Expression getExpression() {
            return m_expr;
        }

        /**
         * @see ExpressionOwner#setExpression(Expression)
         */
        public void setExpression(Expression exp) {
            exp.exprSetParent(FilterExprIterator.this);
            m_expr = exp;
        }

    }

    /**
     * This will traverse the heararchy, calling the visitor for
     * each member.  If the called visitor method returns
     * false, the subtree should not be called.
     *
     * @param visitor The visitor whose appropriate method will be called.
     */
    public void callPredicateVisitors(XPathVisitor visitor) {
        m_expr.callVisitors(new filterExprOwner(), visitor);

        super.callPredicateVisitors(visitor);
    }

    /**
     * @see Expression#deepEquals(Expression)
     */
    public boolean deepEquals(Expression expr) {
        if (!super.deepEquals(expr))
            return false;

        FilterExprIterator fet = (FilterExprIterator) expr;
        if (!m_expr.deepEquals(fet.m_expr))
            return false;

        return true;
    }

}
